Manufacture of lubricants



Patented May 23, 1939 UNITED STATES PATENT OFFICE MANUFACTURE OF LUBRICANTS Indiana No Drawing. Application April 19, 1937, Serial No. 137,764

5 Claims.

This invention relates to the manufacture of lubricants and particularly to the manufacture of synthetic lubricating oils having special properties adapting them to the lubrication of certain types of machinery, such as automatic variable speed power transmissions. In continuous automatic variable speed power transmissions employing extremely high pressures between metal surfaces such as at contact points between balls, rollers and races it is necessary to use a lubricant to prevent galling. However, it is essential to avoid the use of a lubricant which will cause slipping between the surfaces at the contact points, thereby preventing the transmission of power through the mechanism. A machine for testing lubricants for this purpose is described in United States Patent No. 2,045,555, issued to J. D. Almen, June 23, 1936.

From a study of a large number of lubricating oils for this purpose applicants have discovered that certain types of synthetic lubricating oils are especially valuable and more efiective than any of the natural oils or the synthetic oils known to the prior art. The synthetic oils they have investigated were manufactured by the catalytic polymerization of unsaturated hydrocarbons in accordance with the general method described by Brownlee United States Patent 1,309,432, issued July 8, 1919.

We have discovered that synthetic oils prepared from distillates produced by high temperature cracking or reforming of gasoline and especially heavy naphtha are especially valuable for, our purpose. We have also discovered that the co-polymerization of reformer distillate with pinene or turpentine likewise produces a superior oil for lubrication of automatic variable speed power transmissions. By co-polymerization we mean that the liquids are mixed and treated together with a catalyst with the result that they interact to form new chemical products.

In carrying out our process we prefer to subject a heavy naphtha, for example Mid-Continent heavy naphtha, to a reforming-cracking operation at a high temperature of about 1000-1150 F. and preferably at a pressure of about 500-1000 pounds per square inch. Lower pressures, however, of the order of 100 pounds per square inch may be employed. The stock used in this reforming operation may suitably be a heavy naphtha having a boiling range of 250-450 F. Somewhat lighter stocks having a boiling range of 200400 F. may likewise be employed. Cracking may be carried out in a coil or coil and drum apparatus wherein the naphtha is forced through a long coil placed in a furnace and rapidly heated to the desired temperature above 950 F. and the naphtha vapors passed through a soaking section of the coil where the tem- 5 perature is maintained at the desired cracking temperature, for example 1050 F.

The resulting distillate is fractionated to separate high boiling constituents and gases and the highly unsaturated hydrocarbons boiling mostly within the gasoline boiling range are subjected to polymerization with aluminum chloride or other suitable active halide catalyst such as aluminum bromide, boron fluoride, etc. From 25% of catalyst may be used and the catalyst should be agitated with the unsaturated hydrocarbon distillate while maintaining the temperature at 100-300 F. A temperature of 150 F. is satisfactory and the polymerization reaction may be hastened by the use of a promoter such as HCl or aliphatic chlorine compounds, carbon tetrachloride, etc. 11 desired, the entire product of reformingmay be employed and maintained under pressure, only the heaviest' tar and the fixed gases being removed.

After completing the polymerization, which may require several hours, the catalyst is separated from the oil as a sludge and the oil is neutralized and washed in the regular manner. Low-boiling and unchanged hydrocarbons 'are removed by distillation and the distillation may be carried on until the viscosity of the residual oil is about seconds Saybolt at 210 F., although viscosities of about 50 to seconds Saybolt are suitable. The synthetic oil obtained 3 in this manner is free from parafiin wax and possessed of a low pour point which is substantially determinable by the increase in viscosity of the oilat low terperatures. The oil is also characterized by a low viscosity index as calcu- 4o lated by the method of Dean and Davis, Chem.

& Met. Engr., October 1929, page 618. The viscosity index of our special synthetic oils will usually be negative and may be as low as '70 to The addition of pinene and turpentine to the reformed naphtha distillate still further im-' proves the resulting synthetic lubricating oil product and up to 40% of pinene may be employed in this way, although we prefer to use 50 about 10-20%. We may use the turpentine in place of pinene with good results. The follow-. ing. table gives the results of a number of tests made with our synthetic lubricating oils derived from a. variety of stocks by the method 5:

. torque ratio is used herein. it-will be understood to mean therat'io of the eli'ectivetorque t 'of the oil in question compared to this standard bythe above ratios are in some cases-relatively. f small, small difierences represent a 'very large v to oil 'determinedwith the Almen machine. The

data are'presented onthe basis of a torqueratio of '1 forYthe standard.

Viscosity Yield Torque index percent ratio Synthetic oil lrom' 1 Y Ordinary pressure gasoline from I a gas oil +30 16 1. 02 Heavy dist. from cracked gas oil. t 30 22 0.90 Cracked paraflfin wax I 0. 74 .Reformed gascline. -70 -10 1. 10

Reformed gasoline+10% ;turv pentine l4 L-ll Reformed gasoline-+20% turv p .pentine .4; .40 17 L17.

- Reformed gasoline+4ll% t lpentine- .;.L.. l6 1 1.14. Comparative oils:

Solvent extract from Mid-Continent lubricating oil refined... 0.05 East Texas lubricating oil 0. Lard oil 0 5i Although the differences n torque as indicated difference in-.the size. of the equipmentrequired to transmit a givenamount of-power.

'It should be understoodthat we may blend our.

synthetic oils with various other lubricating oils blend themwith various natural oils such asthe East Texas lubricating oil referred min the foregoing table. ,We mayalso blend them with certain modifying agentsysuch'as' pour test depressor's, for exam'ple,' soapslzinlc hydroxy s'tearate,

alun iir 1um naphthenate, .etc., synthetic hydrocarbon resins such as. the polymerization products of.chlorinated paraffin .wax' andnaphthalene, etc. in relatively small amjountsusually of the-order of 1-2% or less. We may alsomodify our synthetic oils 'udth'othersynthetic oils with merizatlon products of isobutylene, especially those obtained by the action of active metal halide catalysts, aluminum chloride and boron fluo- .ricle which give hydrocarbon oils and plastics at various temperatures, especially at low 'tem-- peraturesofitheorderof 40 to- F. Calciumand'sodium soaps may be adde d'asvbody agents to produce a' heavier product resembling- Q-Ithe greases.

1 the improved behavior of our synthetic oils from reformed naphthaor turpentine, we believe that. the, efiect may be associated-with the low sulfur. content; ofthe synthetic oils in combination with low viscosity index, and the peculiar property of the synthetic oils-of decomposing undercon-' Although we donot know the exact reason 'for Particular type ofservice.-

esses such as the process described herein under-- go a depolymerizati'o'nat elevatedtemperatures,

for 'exampletat temperaturesof theorder of 600 F.,.and in -some cases evenmuch lower tempera-- tures of the order. of 400". F. It is therefore possible that our synthetic oil's undergoa decomposition at the point of contact between the surtion; and therefore the torque obtainable in this It should be noted.

v faces ofballs and races, thus'increasing the fricthat this requirement is directly contrary to the Y requirement for those lubricants employed in ordinary extreme pressure lubricatlo'm'for example irr'the lubrication of hypoid gears, metal cutting tools, etc., where it is desired to obtain maximum lubrication at points of high pressure. It is also possible. that'our synthetic oils do not increase in viscosity with extremely high pressure in the same manner as ordinaryoils and therefore they do not provide the undesirable lubrication which causes slipping ,at points of extremely high pressure in the power transmission mechanism; I We.

do" not intend; howeverlpthat'our inventionbe limited by any theory advanced herein'but; only by -the extent of the following claimsq We claim: p a J l. The process of producing. lubricating oils I adapted 'for the lubrication of automatic variable speed powertransmissions comprising subjectanactive metal halide-whereby said unsatu'ratedhydrocarbons are substantially polymerized to a higher molecular weight lubricating 'oils, separating; the -resulting polymerized oil "from sludge and removing fihe unchanged naphtha from. the 4 lubricating oil products.- t

2 The process of claim'l wherein the active metalhalide is anhydrous aluminum chloride. 3.;Tfie proce'ssJofclaim wherein the reformed naphtha is a product of reforming at te mpera-' times between 1000 and- 1150 Ft 4a The proce'ssof claim 1 wherein. thereformed naphtha is a productof reforming a petroleum naphtha havin' a boiling range between 200 and 450? 5. The process 'of producing lubricating oils adapted to the lubrication of 'automatic variablespeed power. transmissions,' comprising subject-. ,ing an unsaturated hydrocarbon -distillate selected fromthe class consisting of reformed naphtha and mixtures of reformednaphtha with pinene to the catalytic polymerizing action 'ofan active "metal halide whereby unsaturated hydrocarbon constituents are polymerized to higher molecular weight lubricating oil, separating the resulting polymerized oil .fro'm .catalyst'fsludge and re- :rnoving" unpolymerized hydrocarbons-from the lubricating oil product.

Emma w. DAMS;

GEORGE M.- MCNULTY.

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